Cortana was pretty good at understanding me. Was much faster to use my voice than touch, for stuff like setting reminders and alarms. Or starting music (it understandably sucked at changing tracks, unless you had headphones).

I was excited for what else they would make it do. But it became clear MS only goal with it was to advertise stuff. And to US only. And when they failed that, they ripped out any useful features from it.